Newbie with a blank screen

I recently purchased a new Asus tablet, not sure what model it is, it wasn't in the box but still had the plastic on the screen. It was working great and I really like it but after about 3 days of use I placed it in my backpack where it sat with a few other things for several days. When I removed it and tried using it I can't get it to turn back on.. that's not entirely true though, the light on the power button lights up and once fully charged turns green, and I believe it is powered on as every now and again I get sound out of it like its notifying me of a text msg or maybe the availability of a wifi signal, but I have no flicker of activity on the screen of any kind. The power may have been on when I placed it in the backpack I'm not sure...a possibility is that the power was on and buttons or things were pressed on the screen that turned the screen off? maybe a brightness switch? I don't know I am just throwing out uneducated guesses in the hope someone has a simple answer. Cant hurt to hope right? I did try to do a factory reset by pushing the power button and volume up button but nothing happened, problem is that I'm not sure if the power was off or not when I tried. Thanks in advance for any help anyone may give.